Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Communications in Theoretical Physics

Concatenated deleting machines and their characteristics

A. Nancy, S. Balakrishnan

Published Mar 1, 2023• 2 citations
Publisher

Abstract

Abstract In this work, we study the performance of one shot and concatenated deleting machines (DMs). We show that the output state of one shot DMs are mixed inseparable, and do not violate Bell’s inequality but can be used as a teleportation channel for all values of the input state parameters. On the other hand, we observe in the concatenation of different DMs that the output states are mixed inseparable and do not violate Bell’s inequality, and cannot be used as a teleportation channel. Further, some important attributes such as inseparability, violation of Bell’s inequality, and teleportation fidelity of the DMs remain unchanged under the order of concatenation. In this context of a teleportation channel, one shot DMs are useful when compared to concatenated DMs.

DOI
10.1088/1572-9494/acb3b4

Related papers

Quantum cloning, Bell's inequality and teleportation

Satyabrata Adhikari, Nirman Ganguly, Indranil Chakrabarty +1 more

We analyse the possibility of using the two-qubit output state from the Buzek–Hillery quantum copying machine (not necessarily a universal quantum cloning machine) as a teleportation channel. We show that there is a range of values of the machine parameter ξ for which the two-qubit output state is entangled and violates the Bell-CHSH inequality and for a different range it remains entangled but does not violate the Bell-CHSH inequality. Further, we observe that for certain values of the machine parameter the two-qubit mixed state can be used as a teleportation channel. The use of the output state from the Buzek–Hillery cloning machine as a teleportation channel provides an additional appeal to the cloning machine and motivation for our present work.

arXiv:0712.1404•Journal of Physics A Mathematical and Theoretical•Sep 15, 2008•13 citations

Nonlocality in quantum cloning states

Jun Liu, Zhiwen Mo

This study investigates the nonlocality characteristics of output states produced by a universal quantum cloning machine, with particular emphasis on the Bell-CHSH inequality violations exhibited by the two-qubit reduced states of cloned outputs. Through systematic analysis, we identify the parameter regimes where these reduced states can effectively serve as quantum channels for teleportation protocols. Our results demonstrate that within specific operational ranges of the cloning machine parameters, the two-qubit reduced states are suitable for quantum teleportation but do not exhibit violations of Bell-CHSH inequalities. Furthermore, we quantitatively characterize the monogamy relations governing Bell-CHSH violations in quantum cloning states across different parameter configurations, revealing fundamental constraints on nonlocality distribution in cloned quantum systems.

Scientific Reports•Jul 1, 2025•0 citations

The use of the output states generated by the broadcasting of entanglement in quantum teleportation

Iulia Ghiu, Catalina Cirneci, George Alexandru Nemnes

In this article, we find a theorem that gives a relation between the maximal fidelity of teleportation and the concurrence of the inseparable $X$ state used as a quantum channel in this process. Furthermore, we evaluate the concurrence of the output states generated by the local and nonlocal asymmetric broadcasting of entanglement and prove that the concurrence is greater in the case of nonlocal broadcasting. We analyze the possibility of using the output states obtained by the broadcasting of entanglement as quantum channels in quantum teleportation. We prove, with the help of the above-mentioned theorem, that all the inseparable states given by the local and nonlocal asymmetric broadcasting of entanglement are useful for quantum teleportation. Finally, we show that the maximal fidelity of teleportation is greater in the case when the second scenario is used, i.e., when the quantum channel is generated by the nonlocal asymmetric broadcasting of entanglement.

quant-pharXiv:2604.12823•Physics Letters A•Apr 15, 2026•2 citations

Teleportation via maximally and non-maximally entangled mixed states

Satyabrata Adhikari, A. S. Majumdar, Sovik Roy +2 more

We study the efficiency of two-qubit mixed entangled states as resources for quantum teleportation. We first consider two maximally entangled mixed states, viz., the Werner state\cite{werner}, and a class of states introduced by Munro {\it et al.} \cite{munro}. We show that the Werner state when used as teleportation channel, gives rise to better average teleportation fidelity compared to the latter class of states for any finite value of mixedness. We then introduce a non-maximally entangled mixed state obtained as a convex combination of a two-qubit entangled mixed state and a two-qubit separable mixed state. It is shown that such a teleportation channel can outperform another non-maximally entangled channel, viz., the Werner derivative for a certain range of mixedness. Further, there exists a range of parameter values where the former state satisfies a Bell-CHSH type inequality and still performs better as a teleportation channel compared to the Werner derivative even though the latter violates the inequality.

arXiv:0812.3772•Quantum Information and Computation•May 1, 2010•33 citations

Entanglement teleportation via Bell mixtures

Sibasish Ghosh A, Guruprasad Kar, Anirban Roy +2 more

We investigate teleportation of bipartite pure entanglement through two equally noisy quantum channel states, namely, a mixture of Bell states. There is a particular mixed-state channel for which all pure entangled states in a known biorthogonal product basis remain entangled after this inexact teleportation, which occurs for the duration of the entanglement. The Werner state channel lacks both these features. The relation of these noisy channels to the violation of Bell's inequality and quantum two-entropy inequality is studied.

arXiv:quant-ph/0107056•Physical Review A•Aug 5, 2002•7 citations

Bell’s inequalities versus teleportation: What is nonlocality?

Sandu Popescu

The nonlocality responsible for violations of Bell's inequalities is not equivalent to that used in teleportation, although they probably are two aspects of the same physical property. There are mixed states which do not violate any Bell type inequality, but still can be used for teleportation.

Physical Review Letters•Feb 7, 1994•535 citations
Abstract In this work, we study the performance of one shot and concatenated deleting machines (DMs). We show that the output state of one shot DMs are mixed inseparable, and do not violate Bell’s inequality but can be used as a teleportation channel for all values of the input state parameters. On the other hand, we observe in the concatenation of different DMs that the output states are mixed inseparable and do not violate Bell’s inequality, and cannot be used as a teleportation channel. Further, some important attributes such as inseparability, violation of Bell’s inequality, and teleportation fidelity of the DMs remain unchanged under the order of concatenation. In this context of a teleportation channel, one shot DMs are useful when compared to concatenated DMs.
We analyse the possibility of using the two-qubit output state from the Buzek–Hillery quantum copying machine (not necessarily a universal quantum cloning machine) as a teleportation channel. We show that there is a range of values of the machine parameter ξ for which the two-qubit output state is entangled and violates the Bell-CHSH inequality and for a different range it remains entangled but does not violate the Bell-CHSH inequality. Further, we observe that for certain values of the machine parameter the two-qubit mixed state can be used as a teleportation channel. The use of the output state from the Buzek–Hillery cloning machine as a teleportation channel provides an additional appeal to the cloning machine and motivation for our present work.
This study investigates the nonlocality characteristics of output states produced by a universal quantum cloning machine, with particular emphasis on the Bell-CHSH inequality violations exhibited by the two-qubit reduced states of cloned outputs. Through systematic analysis, we identify the parameter regimes where these reduced states can effectively serve as quantum channels for teleportation protocols. Our results demonstrate that within specific operational ranges of the cloning machine parameters, the two-qubit reduced states are suitable for quantum teleportation but do not exhibit violations of Bell-CHSH inequalities. Furthermore, we quantitatively characterize the monogamy relations governing Bell-CHSH violations in quantum cloning states across different parameter configurations, revealing fundamental constraints on nonlocality distribution in cloned quantum systems.
In this article, we find a theorem that gives a relation between the maximal fidelity of teleportation and the concurrence of the inseparable XXX state used as a quantum channel in this process. Furthermore, we evaluate the concurrence of the output states generated by the local and nonlocal asymmetric broadcasting of entanglement and prove that the concurrence is greater in the case of nonlocal broadcasting. We analyze the possibility of using the output states obtained by the broadcasting of entanglement as quantum channels in quantum teleportation. We prove, with the help of the above-mentioned theorem, that all the inseparable states given by the local and nonlocal asymmetric broadcasting of entanglement are useful for quantum teleportation. Finally, we show that the maximal fidelity of teleportation is greater in the case when the second scenario is used, i.e., when the quantum channel is generated by the nonlocal asymmetric broadcasting of entanglement.
We study the efficiency of two-qubit mixed entangled states as resources for quantum teleportation. We first consider two maximally entangled mixed states, viz., the Werner state\cite{werner}, and a class of states introduced by Munro {\it et al.} \cite{munro}. We show that the Werner state when used as teleportation channel, gives rise to better average teleportation fidelity compared to the latter class of states for any finite value of mixedness. We then introduce a non-maximally entangled mixed state obtained as a convex combination of a two-qubit entangled mixed state and a two-qubit separable mixed state. It is shown that such a teleportation channel can outperform another non-maximally entangled channel, viz., the Werner derivative for a certain range of mixedness. Further, there exists a range of parameter values where the former state satisfies a Bell-CHSH type inequality and still performs better as a teleportation channel compared to the Werner derivative even though the latter violates the inequality.
We investigate teleportation of bipartite pure entanglement through two equally noisy quantum channel states, namely, a mixture of Bell states. There is a particular mixed-state channel for which all pure entangled states in a known biorthogonal product basis remain entangled after this inexact teleportation, which occurs for the duration of the entanglement. The Werner state channel lacks both these features. The relation of these noisy channels to the violation of Bell's inequality and quantum two-entropy inequality is studied.